Leaving Home for an Extended Period and Not Using Your Water Purifier? Proper Storage and Restart Procedures to Prevent Total Failure

Leaving Home for an Extended Period and Not Using Your Water Purifier? Proper Storage and Restart Procedures to Prevent Total Failure

Whether you’re heading back to your hometown for the Lunar New Year, going on a business trip for two or three months, or leaving your home unoccupied… Many people turn off the water and electricity before leaving, but they often forget about the water purifier. When they return and turn on the faucet, the water comes out yellow and foul-smelling, and the filter cartridges may even be covered in green algae and slime. What’s even more heartbreaking is that in some cases, the pump is completely rusted solid and the pipes are completely clogged—and the repair costs can end up being more expensive than buying a brand-new unit. This isn’t meant to scare you—repair technicians have seen this happen far too often.

Water purifiers installed inside cabinets are most prone to problems during prolonged periods of inactivity.

The length of inactivity makes a world of difference in the severity of the issues.
What water purifiers really fear isn’t being “turned off,” but rather “stagnant water after being turned off.” The water left inside the machine is like a stagnant pool; as temperatures rise, bacteria multiply at an exponential rate. PP cotton and activated carbon filter cartridges have porous structures that adsorb large amounts of organic matter, making them a breeding ground for microorganisms. If the unit is left unused for three to five days, it’s not a big deal—a quick rinse will restore it to working order. But after more than two weeks, noticeable bacterial colonies begin to form inside the cartridges. If left unused for one to two months, the microporous holes in the RO membrane may become clogged with dried-out impurities, and the water stored in the pressure tank will spoil and develop an unpleasant odor.

Residual water inside the water purifier’s filter housings and tubing is a breeding ground for bacteria
The worst case I’ve seen: A user went on a three-month business trip and, upon returning, immediately turned on the faucet to drink the water—resulting in the entire family coming down with diarrhea that very day. When we took the unit apart, the surface of the pre-filter was already green, and the post-filter activated carbon cartridge felt soft and flimsy when squeezed—it had completely lost its adsorption capacity. The RO membrane wasn’t completely ruined, but it took a full half-hour of flushing before the TDS level finally dropped. That was actually a lucky outcome—in some cases, the booster pump, having been idle for a long time, seized up and burned out the moment power was restored, costing several hundred yuan to replace.

The Correct Procedure Before Leaving Home: Three Simple Steps
Step 1: Thoroughly flush the system. On the day before you leave, turn on the filtered water faucet and let the water run continuously for 15 to 20 minutes. The goal is to flush out as much residual water as possible from the pipes and filter cartridges, reducing the water volume in which microorganisms can survive. For RO systems, drain both the purified water and the concentrate. For ultrafiltration systems, simply open the flush valve to flush the system.
Step 2: Shut off the water and power supply, then drain the system. Close the inlet ball valve and unplug the power cord (for models with a power supply). Turn on the filtered water faucet to drain all remaining water from the system until not a single drop comes out. For models with a pressure tank, remember to open the air valve on the tank to drain the water from it as well. This step is crucial—many people only close the water valve without draining the residual water, resulting in that small amount of stagnant water in the pipes soaking the filter cartridges, causing the water to still smell bad when they return.
Step 3: Remove and Air-Dry the Pre-Filters. If you’ll be away for more than a month, we recommend unscrewing the PP cotton and pre-activated carbon filters and placing them in a well-ventilated area to air-dry. These two filters are the least expensive and most susceptible to damage from prolonged exposure to water. There’s no need to remove the RO membrane, as it’s sealed inside the membrane housing; keeping it dry after draining the water will actually extend its lifespan.
💡 For short-term absences (one week or less), no special treatment is needed; simply flush the system for 3 to 5 minutes upon your return. For absences of one to two weeks, drain the system before leaving and flush it for 10 minutes upon your return. For absences longer than one month, follow the three steps above.

When you return, don’t rush to drink the water straight from the tap.
Many people are thirsty as soon as they get home and drink water directly from the filtered tap—but you must never do this. Bacteria have likely already grown in the water purifier’s pipes and filter cartridges during the downtime, so a thorough “restart flush” is essential. First, reinstall the pre-filter (if you removed it earlier), open the inlet ball valve and turn on the power, and let the machine produce water normally. Then, turn on the purified water faucet and let the water run continuously—flush the RO system for at least 30 minutes and the ultrafiltration system for 15 to 20 minutes. If you have a TDS meter, measure the TDS value of the purified water; it should be below 50 to be considered normal. If you don’t have a TDS meter, smell the water to check for any unusual odors and look to see if the color is clear and transparent. If there’s still a musty smell after flushing for half an hour, the pre-filter is likely compromised—replacing it with a new one is a more reliable solution than simply flushing it out.

Once filter cartridges have deteriorated, they must be replaced; flushing cannot restore the activated carbon’s adsorption capacity, and the water in the pressure tank should not be kept. If you forgot to drain the remaining water from the tank before leaving home, you must drain all the water from the tank upon your return, rinse it two or three times, and then resume normal use. The inner walls of the tank are smooth, so in theory, bacteria are unlikely to adhere to them, but water left standing for too long will still spoil, especially in the summer.

Signs That the Filter Cartridges Are Worn Out
If the water still has an odor after rinsing, the TDS level doesn’t drop, or the water production rate has noticeably slowed down—any one of these three issues indicates that the filter cartridges need to be replaced. PP cotton and pre-filter activated carbon are inexpensive—you can get them for just a few dozen yuan—so there’s no need to risk your digestive health just to save a little money. The situation with RO membranes is slightly better; as long as there is no physical damage, they can usually be restored after repeated rinsing. However, if the system has been out of use for more than half a year, the membrane housing may have dried out, cracked, or become scaled, so it’s recommended to replace it outright.

If filter cartridges have deteriorated due to prolonged disuse, replacement is the only solution.
There’s another potential hazard that’s often overlooked: pipe fittings. Water purifiers contain many quick-connect fittings and O-rings. If left unused for a long time, the rubber O-rings may age and deform, leading to leaks once the water supply is restored. After restarting the system, we recommend placing a paper towel under the machine and checking for water stains overnight. If any are found, replace the O-rings promptly.

📋 Action Checklist
Before leaving home: Flush → Turn off water and power → Drain any remaining water → Remove the pre-filter and let it air dry
Upon returning home: Install the filter → Turn on water and power → Flush for at least 30 minutes → Check the TDS level or smell the water
If the unit has been idle for more than 2 months: Replace the pre-filter immediately—don’t hesitate to spend those few dozen yuan